1. Field of the Invention
This invention relates to fluid handling processes and apparatus. More particularly, this invention relates to a method and an apparatus for mixing gas or other fluids into a liquid stream.
2. Description of the Related Art
The injection of liquids into liquid streams using an injector is well-known. Such systems are widely used in the agricultural field to inject fertilizers and insecticides into a pressurized water stream of irrigation systems. Injectors for such irrigation applications have long been known. For example, see FIGS. 1-3 from U.S. Pat. No. 4,123,800 to Mazzei which show, respectively, a cross-sectional, outlet axial and inlet axial views of such an injector.
The injector shown here is characterized by having general axial symmetry and being shaped like a Venturi tube with a throat area near its inlet. It also has an annular ring or chamber (see 26 in FIG. 3) that surrounds the device's throat, with this ring having ports (see 40 in FIG. 3) through which an additive liquid can be entrained into the carrier liquid passing through the injector. Grooves (see 35 in FIG. 2) in the downstream portion of the injector serve to add swirl to the flow and aid in mixing the additive and carrier liquids.
Over the years it has been learned that an injector of this type is also suitable for adding gases to a liquid stream. See FIGS. 4 and 5 from U.S. Pat. No. 5,674,312 to Angelo Mazzei. Again, we see that this air-liquid injector is also characterized by having general axial symmetry and being shaped like a Venturi tube with a throat area near its inlet. It also has an annular ring or chamber that surrounds the device's throat, with this ring having ports or a groove through which a gas can be entrained into the carrier liquid passing through the injector.
Examples of gases which can usefully be injected into liquids are air, chlorine, oxygen, and ozone. Applications vary from small installations such as home spas and swimming pools to city and regional water supplies, as well as to irrigation systems and aquaculture applications.
The injection of these gases, while beneficial for their intended chemical effects (e.g., ozone into water helps to sanitize the water), is not without some possible complications. For example, the discharge of ozone into the atmosphere is very strictly regulated. Thus, when ozone is injected into water, only small amounts of any excess ozone, which is not dissolved in the water, are permitted to be discharged into the atmosphere. Thus, in water treatment systems, better ozone in water mixing methods and apparatus are always desirable.
Examples of other prior art injectors are found in U.S. Pat. Nos. 2,361,150, 3,799,195, 4,344,752, 5,743,637, 5,863,128 and 6,173,526.
Despite much prior art relating to such liquid-liquid and gas-liquid injectors, there still exists a need for further technological improvements with respect to these devices.
3. Objects and Advantages
There has been summarized above, rather broadly, the prior art that is related to the present invention in order that the context of the present invention may be better understood and appreciated. In this regard, it is instructive to also consider the objects and advantages of the present invention.
It is an object of the present invention to provide a gas-liquid injector which can operate at higher mixing and gas dissolution efficiencies than other competitive devices.
It is another object of the present invention to provide a gas-liquid injector that causes minimal pressure losses in the carrier liquids that flow through it.
It is yet another object of the present invention to provide a gas-liquid injector that can operate so as to allow higher suction pressures to be used to draw gas into the liquid.
These and other objects and advantages of the present invention will become readily apparent as the invention is better understood by reference to the accompanying summary, drawings and the detailed description that follows.